When you work on a computer you produce data. The data is stored on a data storage medium. In a business environment it is often stored on the hard disks of a server. In a home situation it is often stored on the hard disk of the local computer where you are working on. So a hard disk is a storage medium for your data. A hard disk is the most used medium and there are several different types of hard disks and also there are different types of storage media.

Types of storage media:

Hard disks DVD’s CD's Floppies Tapes

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Hard disks

Hard disks are the most used data storage media to store data. Every computer has a hard disk to store the data. There are several different types of hard disks. Not every hard disk works on the same speed. Also the technique can be different and therefore also the connectors can be different.
As I said before there are several speeds and several types. Below there is a list op types and speeds.

Types of hard disks
There are several types of hard disks available on the market. There are IDE, SATA, SCSI, USB and FIREWIRE hard disks. I will describe each type below.

IDE hard disk
The IDE hard disk is until know the most used hard disk in computers but in the future the SATA hard disks will be used more and more. A IDE hard disk is also called ATA or PATA hard disk. This means Parallel ATA and can transmit data on a normal speed and is a bit slower then the SATA hard disks.
You can recognize a IDE hard disk at the connector. It has a 40 pins connector and it has quite a big power connector.

DVD’s are data storage media where you can store your data on using a DVD writer. If you want to move much data around this could be a perfect solution. On a single DVD you can store up to 4,7 GB of data. On a CD you can store up to 700 MB so a DVD has much more capacity then a CD. On the market there are several different DVD writers available. There are DVD+R, DVD-R, DVD +R and DVD-R, DVD-DL, DVD-RW.
For example:
You have a DVD+R writer in your computer and you have an empty DVD+R disc. You burn the data to the disc. This is possible because your DVD writer supports DVD+R.
After the disc is burned you go to your friend to copy the disc but your friend has only a DVD-R writer so this is not possible because this DVD writer doesn’t support DVD+R.
Fortunately, most newer DVD writers support both.



The DVD-DL means Dual Layer and it has a capacity of 8.5 GB. So on such a disc you can store even more data then on a normal DVD. Using a DVD writer or a dual layer dvd drive you can also burn CD’s.
Near a DVD drives and CD drives there are also drives which is called a CD DVD combo drive. Such drive is a drive which can write and read CD's and can only read DVD's and can not write DVD's.

Below there is a list of what functions most DVD writers support at the moment.

Example of what a single DVD writer supports.

Function	Drive Speed
Read (CD)	48 x (7,200 KB/s)
Read (DVD)	16 x (21,600 KB/s)
Write (CD-R)	48 x (7,200 KB/s)
Write (CD-RW)	32 x (4,800 KB/s)
Write (DVD-R)	18 x (24,300 KB/s)
Write (DVD-RW)	6 x (8,100 KB/s)
Write (DVD+R)	18 x (24,300 KB/s)
Write (DVD+RW)	8 x (10,800 KB/s)
Write (DVD-R) Double layer	8 x (10,800 KB/s)
Write (DVD+R) Double layer	8 x (10,800 KB/s)
Write (DVD-RAM)	12 x (16,200 KB/s)

CD's

A CD is also a data storage medium where you can store your data on using a CD writer or DVD writer. On a normal CD you can store up to 700 MB. The capacity of a CD is not that much but it is ideal for moving data like documents and a photos on it. So if you want to move smaller files you can burn your data to a CD. Also for CD writers there are several functions and speeds available on the market like a CD-R (recordable) or a CD-RW (rewritable).

On a floppy you can store just a small amount of data on. It has a capacity of 1.44 MB. To move around small documents like a Word document or Excel document this type of data storage medium can be used without a problem. Several years ago the floppy was the medium to store your data on but now it is mostly used for boot disks or DOS programs.

This type of data storage medium is not much used in a home situation but is used in larger companies for data storage and backup their data. These data storage tapes must be put into a tape unit to store data on. You can call tape units also a data storage drives.
Also tapes have different capacities but common tapes have a much larger capacity then CD’s or DVD’s. There are tapes with a capacity like 10 GB up to 300 GB and more. So that’s why many companies use tapes to store or backup their data.